For food cooking, various techniques have been developed to date and these include the use of an oven with or without a grill, a classical casserole or a steamer pot, a frying pan or a microwave oven.
Each of these devices provides for various cooking possibilities and each may be used for a particular foodstuff depending upon its structure, the way in which it is to be prepared, whether it is frozen or not and whether it is fresh or dried.
To allow all of the various techniques of cooking to be used at one location, e.g. a home or a foodstuff establishment, thus requires considerable investment.
In many of the devices used heretofore to cook foods, the thermal yield is minimal and the apparatus is considered to have poor efficiency, wasting comparatively large amounts of heat. This loss of heat can be a result of convective flow of heat away from the site at which the thermal energy can be used efficiently, radiant loss of heat and conductive loss, e.g. to structures having a high thermal inertia.
A variety of difficulties are also encountered in the cleaning of such cooking apparatus.
French Pat. No. 1,596,525 and U.S. Pat. No. 3,414,709 describe processes and devices for reheating of culinary platters utilizing two infrared radiation sources spaced apart and defining between them a space in which the closed and sealed receptacle for the platter can be received. This receptacle is composed of a material which is transparent or permeable to infrared rays. Because of the construction of these devices, the infrared energy is transmitted exclusively by radiation to the food or is directed upon the food and the receptacle to heat the food exclusively in the first case and both the receptacle and the food in the second case. However, these systems are not amenable to true cooking of foodstuffs and certainly cannot be used for a wide variety of foodstuffs and cooking preparation in a wide variety of ways. A universally applicable approach to cooking, for example, is not suggested in this patent.